The oxidation of tires typically results in a reduced lifespan of the tire. The underinflation of tires also reduces tire lifespan and is the source of other detrimental effects such as reduced rolling resistance and irregular wear. Therefore, it is important to improve the endurance of tires in relation to tire pressure retention and to the oxidizing processes of the rubber compositions and the metallic or textile reinforcement thereof.
One known method of reducing oxidation phenomena has involved using a layer of butyl rubber, which is substantially impermeable to oxygen, that is applied to the inside wall of the tire. This use restricts the amount of oxygen coming from the tire inflation air that gets to zones of the tire that are particularly sensitive to oxidation. Unfortunately, butyl rubber is not totally impermeable and the flow of oxygen into the body of the tire, though reduced, produces undesirable oxidation phenomena over the long term as well as underinflation.
Another way to avoid oxidation problems is to trap the oxygen chemically by the accelerated thermal oxidation of a rubber composition that acts as a buffer, located between a main source of oxygen and the zone to be protected against oxidation phenomena. For example, such a buffer composition is located between the inside face of the tire liner, composed of butyl rubber, and the carcass ply to reduce the amount of oxygen that comes into contact with the carcass ply from the inflation air. Unfortunately, the use of these buffer compositions is believed to result in oxidation of the rubber in that zone. It also does not impact the loss in inflation pressure due to oxygen absorption by the tire.
Lastly, it is known to use nitrogen gas and propellants including gas-generating agents, in place of air, to fill the air cavities of mounted tires, i.e. tires already situated on the tire rim. However, these uses require either a nitrogen source and/or after market canisters including the nitrogen or gas-generating agents.
Accordingly, there is a need for an improved method of reducing oxygen content in air cavities of mounted tires to increase the lifespan of the tire, such as by reducing the oxidation of the tire and increasing tire pressure retention.